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.` California Regional Water Quality Control Board <br /> Central Valley Region <br /> Robert Schneider Chair <br /> Alan C.Lloyd Ph.D. Arnold Schwarzenegger <br /> Secretary for Sacramento Main Office ^��� ��,� Governor <br /> Environmental Internet Address: http://www.waterbouds.ca.gov/cenvaly If`�_ \,V// U <br /> 11020 Sun Center Drive 11200 Rancho Cordova CA 95tr <br /> Protection Phone(916)464-3291 Fax(916)464-4797 <br /> FEB - 3 2006 <br /> 1 February 2006 ENVIRONiv1ENT HEALTH <br /> PERf,'IT/SERVICES <br /> Mr. Paul Supple <br /> Atlantic Richfield Company <br /> P.O. Box 6549 <br /> Moraga, CA 94570 <br /> REVIEW OF PILOT STUDY EVALUATION REPORT,ARCO/BP FUEL TERMINAL, <br /> 2700 WEST WASHINGTON STREET,PORT OF STOCKTON, SAN JOAQUIN <br /> COUNTY <br /> Staff of the Central Valley Regional Water Quality Control Board (Central Valley Regional <br /> Board) reviewed the 28 September 2005 Pilot Study Evaluation, Enhanced Bioremediation <br /> Nitrate/Sulfate Injection (Report) submitted by URS Corporation(URS) on behalf of Atlantic <br /> Richfield Company, Remediation Management(ARCO) for the ARCO/BP Stockton Fuel <br /> Terminal 440T in Stockton (site). The Report discusses the results of the nitrate/sulfate injection <br /> pilot study performed from May 2004 to September 2004 and provides an evaluation of this <br /> technology and its effectiveness at reducing groundwater petroleum hydrocarbon concentrations <br /> at the site. The Report was submitted in accordance with the requirements of Waste Discharge <br /> Requirements (WDR) Order No. R5-2003-0164. <br /> Increases in dissolved nitrate and sulfate concentrations were observed only at Zone A <br /> monitoring well AR/MW-5A, located about 6 feet downgradient of the injection wells. <br /> Monitoring of groundwater physical parameters (dissolved oxygen, oxidation-reduction potential, <br /> temperature, pH, and electrical conductivity) and nutrient content (phosphorous, orthophosphate, <br /> and ammonium as nitrogen) suggests that there were no observable effects on these parameters <br /> due to the pilot study injections. Mann-Kendall statistical analysis of the groundwater chemical <br /> data indicates that a significantly decreasing hydrocarbonconcentration trend could be <br /> established only for well AR/MW-5A since the final nitrate/sulfate injection. ARCO estimates <br /> that the treatment area extended no farther than 12 feet downgradient of the injection wells <br /> following the 2004 pilot study injections. <br /> ARCO recommends expanding the pilot study by increasing the area of nitrate/sulfate solution <br /> injection by adding more injection points, as well as increasing the mass injected through an <br /> increase in concentration or injection rate. ARCO recommends use of a tracer, such as bromide, <br /> to evaluate the rate of transport of nitrate and sulfate at the site. In addition, ARCO proposes that <br /> data collected during the initial pilot study be considered for the development of new baseline <br /> limits for nitrate and sulfate concentrations at downgradient compliance well AR/MW-IA in the <br /> California Environmental Protection Agency <br /> 0 Recycled Paper <br />